A randomized trial of adding a plano lens to atropine for amblyopia

BackgroundSome children have residual amblyopia after treatment with atropine eyedrops for amblyopia due to strabismus and/or anisometropia. We conducted a randomized clinical trial to evaluate the effectiveness of augmenting the effect of atropine by changing the lens over the fellow eye to plano in children with residual amblyopia.MethodsA total of 73 children 3 to <8 years of age (mean, 5.8 years) with stable residual amblyopia (range, 20/32 to 20/160, mean 20/63+1) were enrolled after at least 12 weeks of atropine treatment of the fellow eye. Participants were randomly assigned to continuing weekend atropine alone or wearing a plano lens over the fellow eye (while continuing atropine). The primary outcome was assessed at 10 weeks, and participants were followed until improvement ceased.ResultsAt the 10-week primary outcome visit, amblyopic-eye visual acuity had improved an average of 1.1 lines with the plano lens and 0.6 lines with atropine only (difference adjusted for baseline visual acuity = + 0.5 line; 95% CI, −0.1 to +1.2). At the primary outcome or later visit when the best-measured visual acuity was observed, the mean amblyopic-eye improvement from baseline was 1.9 lines with the plano lens and 0.8 lines with atropine only.ConclusionsWhen amblyopic-eye visual acuity stops improving with atropine treatment, there may be a small benefit to augmenting atropine therapy with a plano lens over the fellow eye. However, the effect was not statistically significant, and the large confidence interval raises the possibility of no benefit or a benefit larger than we observed. A larger study would be necessary to get a more precise estimate of the treatment effect.